Hunger in the spiritual sense is a yearning to be filled with spiritual awareness. In dreams this can be experienced as an actual physical feeling of hunger. Emotionally when we are tired or upset we have the need to be comforted and cherished. There is something lacking and the dreaming mind can translate this into hunger. From a completely practical perspective, if we go to bed hungry our dreams are likely to reflect this fact and register that we need food or sustenance. Consult the entries for Emotions, Food and Yearn for clarification.